This invention relates to temperature-sensing and indicating means and more particularly to an electromechanical device for storing an indication of the maximum temperature range which has occurred in the surrounding environment during a period of time.
Powered vehicles and other systems having an internal combustion engine, hydraulically operated implements or any of various other components which may operate at elevated temperatures, are often provided with some form of temperatureindicator which either displays a reading of current operating temperature or else lights a warning lamp if operating temperature should exceed a predetermined maximum value. These instruments are primarily for the purpose of altering the operator to a possible malfunction or to a need for maintenance. Such instruments are not very adaptable to determining the maximum operating temperature which may occur in an engine or other vehicle component during a prolonged period of operation such as a period of several weeks or months. As a practical matter, the operator does not continually watch the temperature indicator nor make extensive detailed recordings of temperature readings.
Information on the maximum operating temperatures which may be encountered in an engine, hydraulic component or the like of a vehicle over a long period of time may be useful to the operator or to maintenance personnel and may also by highly important to design engineers. For example, when a particular model of engine is designed, it is provided with a cooling system typically including a radiator, a fan, a cooling pump and the like and these cooling system components are a significant factor in determining the bulk, weight and ultimately the cost of the engine. The size or capacity of the cooling system is initially based on an estimate of what may be required in the way of cooling capacity in the typical usages to which the engine model will eventually be put. It is possible that this initial estimate may be inaccurate. If the engine has been provided with insufficient cooling capacity, that fact soon becomes evident to users of the engine and the information soon reaches the manufacturer who may then modify the cooling system to provide such additional capacity as is needed. On the other hand, if an engine has been provided with too much cooling capacity for the uses to which it is typically put, that information may not become evident for a long period if at all.
The disadvantages of an engine or other vehicle component with less than adequate cooling capacity are evident. It is less obvious that there are disadvantages to manufacturing a given model of engine or the like with more cooling capacity than is needed for the typical usage of the engine. To the extent that excess cooling capacity has been provided, there is excess weight, bulk and complication in an engine and fuel consumption is adversely affected. Similar considerations apply to other vehicle components having cooling means. The presence of an unnecessarily large cooling system ultimately means that the costs of both manufacture and operation of the engine or other component are unnecessarily high. A compact, durable and economical device which can be installed on a representative sampling of engines or other components for an extended period of time and which will detect and store an indication of the maximum temperature range which has occurred during a period of time may enable manufacturers to learn more quickly of a situation where the cooling or lubricating system of a particular vehicle component has more capacity than is really required for the typical usages to which the component is being put.
A highly advantageous form of instrument for this purpose is disclosed in applicant's copending application Ser. No. 705,844, filed concurrently with the present application and entitled "MAXIMUM TEMPERATURE-INDICATOR". This copending application discloses a wholly mechanical maximum temperature indicator which may be installed on a vehicle for a long period of time and which provides a visual indication of the maximum temperature which has occurred during that period of time.